In order to change your ARK server map, you will need to first log into the control panel located at http://cp.chicagoservers.co
Once there, you can select a premade commandline that will only change the map.
Or, you can create a custom commandline with additional parameters as pictured below. Select each checkbox for each field you want to become a part of the commandline.
Click save. Select that command line and your server will restart with your new parameters.